


Gen Just Wants Cola

by bummy_bum



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Anal Beads, Anal Fingering, Anal Sex, Blow Jobs, Dildos, Dirty Talk, Edgeplay, Edging, Established Relationship, Hand Jobs, Japanese Rope Bondage, Light BDSM, Light Bondage, Light Dom/sub, M/M, Orgasm Delay/Denial, Plot What Plot/Porn Without Plot, Sex Toys, Smut, kinro and ginro are only in it for a little
Language: English
Status: Completed
Published: 2020-01-22
Updated: 2020-03-23
Packaged: 2021-02-27 10:49:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 6,911
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22365922
Author URL: https://archiveofourown.org/users/bummy_bum/pseuds/bummy_bum
Summary: Gen just wants some cola, but Senkuu has something else in mind.
Relationships: Asagiri Gen/Ishigami Senkuu
Comments: 49
Kudos: 308





	1. Chapter 1

**Summary for the Chapter:**

> Senkuu invents lube.

**Notes for the Chapter:**

> this is my first time writing smut, so I hope you guys like it! (*꒦ິ꒳꒦ີ)

“Here they go again,” Chrome grumbled as he put on his sound-cancelling headphones that he created especially for nights like this. For the past month, Gen and Senkuu had met at the observatory every night. Most nights, they would just sit and talk; however, recently, a lot more than talking was going on and Chrome could unfortunately hear it all.

* * *

Gen walked through the entrance to the observatory, eyeing his boyfriend who had been looking through the telescope. “Senkuu-chan,” he cried out, proceeding to hug him from behind. “Can you make me some cola please.”

Senkuu had the most malicious look on his face, “If you want some cola, you’ll have to do something for me, Gen.” Gen released his hold of the man. Senkuu proceeded to pull out a jar full of something slimy.

“What’s that?”

“I created lube.” Senkuu grinned. “Want to make a deal?”

Gen had a look of shock in his eyes but also a hint of curiosity. “Let me hear it.”

“Don’t come for 8 minutes, and I will make you some cola.”

Barely letting Senkuu finish his sentence, Gen responds, “Deal, Senkuu-chan.”

“Take off your clothes.”

Gen obediently began undressing until he was completely nude. He sat down on a pallet he and Senkuu had put there since they frequently ended up on the floor. Senkuu approached him with his jar of lube and knelt down on the pallet in between Gen’s legs that he slightly spread apart. He dipped his hand into the jar, covering it in the homemade lube, made of nagaimo and coconut oil.

“Senkuu-chan, how will you know if I last 8 minutes?”

“Don’t worry, I will be setting a timer in my mind.”

Senkuu brought his face inches away from Gen’s, causing Gen to close his eyes in preparation of a kiss. However, instead of a kiss, his cock was met with Senkuu’s hand. The sudden, unexpected touch caused Gen to let out a moan.

Senkuu slowly stroked the length Gen’s cock and rubbed his thumb on the head. Gen’s face became completely flushed. He gradually picked up the pace until Gen became fully erect. “Look at how hard you are already? It’s only been 1 minute and 12 seconds…”

Gen’s eyes widened in astonishment.  _ 1 minute and 12 seconds!? How am I going to last for 7 more minutes— _ His thoughts were cut short with Senkuu’s abrupt change in speed. Senkuu jerked Gen’s cock rapidly causing pre-cum to begin dripping out. He teased his tip, maneuvering his thumb over Gen’s most sensitive spots.

“Senkuu-chan please!” Gen cried out. “I’m about to come!!”

“You must not want your cola, then…you’re at 2 minutes and 20 seconds,” Senkuu teased.

“I—I…” Gen whimpered, right before Senkuu released his grip.

“At this rate, you’re definitely not getting your cola.”

“Don’t doubt me just yet, Senkuu-chan,” Gen sneered back at Senkuu as he gripped his cock once again. 

He slowly started to stroke it once again, making his grip slightly tighter than before. He made sure to squeeze especially tight at the head.

Senkuu took his other hand and began massaging Gen’s balls, sending a drawn out moan. “Are you going to come?”

“No, not yet!”

“Good. You’re at 3 minutes.”

Senkuu released Gen’s cock and used his palm to rub the tip causing Gen to squeal. “Senkuu-chan, that feels weird...” His breaths came out harder as he tried not to come. 

“Senkuu...Senkuu-chan...I don’t think I can hold it anymore...” His cock was throbbing. “I’m going to come!” Senkuu immediately stopped touching Gen. His cock twitched vigorously, but he did not come. “See Senkuu-chan, I didn’t—Ah...Ahh!”

Once again, Gen was interrupted by Senkuu’s touch. This time Senkuu used both of his hands, gripping Gen’s cock even tighter. The wet sounds of his hand sliding up and down, and all the erotic faces and noises Gen was making caused Senkuu to feel a warmth within his body and made him rather aroused. However, he could tell Gen was about to reach his climax.

Another minute passed, and Gen was becoming impatient. His hips began moving on their own, pounding against Senkuu’s hands. The cola was the last thing on Gen’s mind at this moment, the pleasurable feeling of Senkuu’s hands around his cock was completely satisfying. “Gen, you still have 3 minutes and 55 seconds left…”

“I don’t care…hnn…I want to come Senkuu-chan…” Gen let out another moan, they were uncontrollable at this point.

Senkuu’s face reddened and a devilish smile protruded. Gen’s body trembled beneath his hands, Senkuu couldn’t help but stroke him unbelievably faster than he had before.

“Senkuu-chan!” Gen cried out. “Please don’t stop…ngh…nghh…” Senkuu considered refusing Gen’s request, but by the look on his face, he could tell that Gen was ready to come.

“I’m coming!” Gen panted. “I-I-I’m coming! I—Ahhh!” Gen’s hips thrusted into the air. Unruly moans exited his mouth as he finally came onto Senkuu’s hands and a bit got onto his face. “I’m sorry, Senkuu-chan,” Gen apologized as he reached up to wipe off the cum on his face.

“I don’t mind,” Senkuu reassured Gen, grabbing his hand and licking the cum off his fingers. “I really don’t. I love your taste.”

Gen somehow became redder than he already was. He attempted to sit up, but his body was unresponsive.

Senkuu got up to get a blanket from a trunk sitting in the corner of the observatory and placed it over Gen.

“Senkuu-chan, come here.”

Senkuu leaned toward his boyfriend’s face who immediately wrapped his arms around his neck and started kissing him. He then bit his lip, slightly harder than what would be considered pleasurable. “Ouch!” Senkuu exclaimed. “What was that for?”

“For making me come too fast,” Gen whined. “How long did I last anyways?”

“4 minutes and 23 seconds,” Senkuu chortled, “Not even close. I guess no cola for you.”

Gen folded his arms in disappointment. “Can you make me cola tomorrow? Please, Senkuu-chan.”

“Want to make another deal?” Senkuu had a rather sinister appearance.

Gen had no idea what Senkuu could have in store for him, but he absolutely could not refuse—he really wanted some cola.

**Notes for the Chapter:**

> please let me know what you think!
> 
> stay tuned to see what Senkuu invents next...heheh


	2. Chapter 2

**Summary for the Chapter:**

> Senkuu invents a flesh light.

**Notes for the Chapter:**

> thank you for all the hits, kudos, and wonderful comments!!!!
> 
> fun fact: i learned that senkuu actually invented lube in canon! LOL (Ch 132) 
> 
> ~enjoy~

It had become night time once again. Chrome was sound asleep, already wearing his soundproof headphones in preparation of the events he was sure would transpire that night. Meanwhile, Senkuu and Gen met in the observatory as usual.

“What are we doing tonight, Senkuu-chan?” Gen inquisitively questioned his boyfriend.

Senkuu smirked as he presented a tube-like object to Gen.

“What is that?”

“I invented a flesh light!”

Gen’s eyes widened. “Oh?” He grabbed the flesh light from Senkuu’s hands and observed it. He had never used a flesh light before, so he had no expectations for how it was going to feel. He noticed some sort of knob at the top. He twisted it but was only able to turn it three times and heard a click at every turn. “What is this for?”

“That adjusts the tightness of the grip.” Senkuu couldn’t control the devilish smile that broadened upon his face. “Think you can last 8 minutes, Gen?”

“Of course I can!” Gen confidently answered, though he looked unsure. “Today is the day I get my cola!”

Senkuu heavily doubted that Gen could last that long. He estimated that Gen would only last 3 minutes, since earlier that day Senkuu had tested out the flesh light and only lasted 5 minutes before reaching his climax—not that he would inform Gen of that.

Without Senkuu saying anything, Gen was already unclothed, waiting for Senkuu on the pallet. “Come on Senkuu-chan, I’m getting horny.”

Senkuu eyed Gen’s half-hard cock and knew that he wasn’t lying. “One second!” He quickly made his way over to the trunk in the corner of the room and grabbed the jar of homemade lube.

He returned to the pallet and studied Gen’s naked body in awe. “Senkuu-chan, are you just going to stare at me or are you going to make me come?” Gen spread his legs and grabbed onto Senkuu’s arm, pulling him closer as he laid back.

Senkuu took the flesh light and filled it with lube and made sure it was on the lowest setting of tightness. He used the opening of the flesh light to stroke against the length of Gen’s cock while pushing it against his abdomen. Gen let out a small gasp.

He toyed with his cock a little more until it was hard enough to enter the flesh light. He slowly slid Gen’s cock inside from the tip all the way down to the base and began stroking it, steadily increasing his pace.

Gen’s body began reacting in unfamiliar ways. The feeling was completely different than Senkuu’s touch—not that it was better…just different. Compared to the gentle and warm touch of Senkuu’s hand, the flesh light felt more intense and stimulating.

Suddenly, Senkuu began pumping as fast as he could. Gen’s breaths became shorter and prolonged moans exited his mouth. Senkuu removed the flesh light, allowing Gen’s cock to slap down against his stomach.

Gen caught his breath and thought,  _ How much time has even passed!? I’m already this hard...  _ “Senkuu-chan…how long has it been?”

“2 minutes and 23 seconds.” Senkuu proceeded to rub the entrance of the flesh light against Gen’s cock again. “I think it’s time to increase the tightness. Show me how much you want your cola, Gen,” Senkuu teased.

Gen’s face scrunched as he tried his best to control his body. His cock was engulfed by the flesh light again. This time, Senkuu performed short, quick pumps, allowing Gen’s dick to fall out of the flesh light each time. The flesh light squeezed his cock significantly more than before. The soft, slimy texture titillated the head of his cock, causing Gen’s toes to curl.

Gen looked up to Senkuu who was staring at his cock. Soon, Senkuu caught Gen’s gaze and bit his bottom lip as he started to aggressively pump the flesh light, without giving Gen’s cock a break. Senkuu removed the flesh light to reveal Gen’s throbbing cock, dripping wet in precum.

“Senkuu-chan, why’d you stop,” Gen cried. He sat up and grabbed Senkuu’s hand that was holding the flesh light and moved it, so it rubbed against his cock. “Keep going.”

“You still have 4 and a half minutes left, Gen…”

Gen brought his face closer to Senkuu’s. “Please…”

That was all Senkuu needed to hear. He twisted the knob on the flesh light to the tightest setting, then shoved Gen’s cock back inside. “Ahhh!” Gen moaned loudly while leaning his head back as he supported himself up with his arms. The flesh light gripped his cock so tightly, he had never felt anything like this before. Senkuu slowly pumped the flesh light up and down.

“Senkuu-chan,” Gen breathed out. “Faster...ngh..”

The way Gen said Senkuu’s name made him blush. He started pumping faster, to satisfy his boyfriend’s request. 

As Senkuu slowed his pace, Gen got onto his knees and wrapped his arms around Senkuu’s neck. Senkuu held onto the flesh light with both hands as Gen began thrusting into it on his own. He couldn’t keep his eyes off his own cock; he thought the way it entered and exited the flesh light was so hot.

Senkuu lightly grazed his lips over Gen’s ear and whispered, “I’m surprised you’ve lasted this long. It’s been 5 minutes…” then gently nibbled on his lobe. Senkuu slightly lifted his head to view Gen’s neck, which looked a soft pale, and he impulsively began to kiss it and couldn’t help but leave a mark.

“…Ahh…ngh…”

Gen held onto Senkuu tighter, laying his face into his shoulder. His strokes became more paced out, but he did them harder, going as deep as he could into the flesh light. “I-I think I’m…ahhh…about to come…Senkuu-chan…nghh…” Gen was nearly incoherent. 

Although Gen’s legs were trembling, Senkuu started pumping the flesh light once again, increasing his pace with each stroke.

“Senkuu-chan...I’m going to...I’m going to come...Ahhh...”

“Not yet Gen.” Senkuu pulled the flesh light off Gen’s cock that was twitching intensely.

“I’m surprised you didn’t come Gen. It’s been 6 minutes.” He looked down at Gen’s cock. “It looks like it’s about to explode,” Senkuu laughed.

“Well...nghh...ahh!” Before Gen could even respond, Senkuu had already pushed Gen’s sensitive cock back into the flesh light. Gen threw his head back as he held onto Senkuu’s shoulder.

“I don’t think I’ll last much longer...Senkuu-chan.”

Senkuu smirked as he tried as hard as he could to make Gen come. “Do you want to come Gen? I’ll make you come.”

Gen couldn’t respond: the only sounds that came from his mouth were moans. His breath pattern drastically changed; Senkuu could tell Gen was almost at his limit.

He stroked his cock a few more times with the flesh light and then pulled it off.

Gen laid back onto the pallet and came all over his abdomen, not even able to moan anymore—only some scattered breaths came out.

“Se-Senkuu-chan...do I get cola?”

“Sorry Gen, that was only 6 and a half minutes.”

Gen looked disappointed. 

“Would you have rather had cola?” Senkuu questioned as he began kissing Gen’s abdomen, licking up his cum.

Gen blushed. Of course, he wanted cola, but nothing could beat a hot and steamy night with Senkuu.

Senkuu cleaned Gen and got the blanket from the trunk. He laid next to Gen, holding him closely. They were both exhausted, but before they went to sleep, Senkuu whispered into Gen’s ear, “I’ll have something even more fun for you tomorrow.” Then kissed his lobe lovingly. “Goodnight.”

**Notes for the Chapter:**

> me pouring my soul into writing smut: (;´༎ຶٹ༎ຶ`)


	3. Chapter 3

**Summary for the Chapter:**

> Senkuu invents anal beads.

**Notes for the Chapter:**

> had to do some research on anal beads lmao
> 
> ENJOY!!

The night sky was extremely clear in the Ishigami village once again.

“Senkuu-chan, is this Saturn?” Gen excitedly questioned Senkuu as he looked through the telescope.

Senkuu stepped in front of his boyfriend and peered into the eyepiece. “You’re right, Gen,” Senkuu replied, confirming Gen’s speculation.

Gen wrapped his arms around Senkuu’s waist and pressed his head against his back. “Senkuu-chan, I really think I can get the cola today. I’m prepared.”

Senkuu lifted his head from the telescope and a smirk appeared on his face. “Oh, are you really…” Senkuu suddenly felt something pushing against him. “Are you already hard?!”

Gen squeezed Senkuu tighter. “I told you I’m ready.”

Senkuu turned around, and kissed Gen on his forehead. “One second.” He walked over to the trunk and picked up something that was wrapped in cloth. He pulled out the mysterious object revealing a line of ten beads connected by some kind of cord, varying in size.

“Anal beads!?”

Senkuu laughed deviously. “You sure you’re still ready?”

_ Another toy I have never used before.  _ Gen was anxious about how the anal beads would feel.  _ What if a bead gets lost inside me?! _

A look of terror fell upon Gen’s face as more unwanted scenarios filled his mind. “Gen…are you okay?”

Gen came back to reality. “We don’t have to do this, if you don’t want…you just won’t get any cola,” Senkuu baited, but then reassured him, “I’ll be gentle.”

Although Gen’s senses were telling him to sit this one out, he was already taking off his clothes and heading to the pallet. 

Senkuu made his way over with the lube and beads. “I’m going to loosen you up first, I’m not counting this towards your eight minutes though—”

“WHAT!?” Gen interjected. “UNFAIR! You better make it count Senkuu-chan!”

Senkuu grinned at his reaction, which he had already anticipated. “You must really want this cola, Gen.” Senkuu took some of the lube and rubbed it on Gen’s hole, causing him to let out a small gasp due to the cold touch. He rubbed Gen’s entrance a bit more before inserting a finger.

“You’re so tight,” Senkuu murmured as he made direct eye contact with Gen, causing his face to flush. Senkuu slightly bent his finger while moving it back and forth, searching for Gen’s prostate.

“Nghh...”

“Found it.”

Senkuu continued to slowly finger Gen, hitting the same spot every time; a soft whimper escaped Gen’s mouth with each stroke.

“Hahh!” Gen moaned as Senkuu added another finger, increasing the pace. He grabbed Senkuu’s wrist. “Senkuu-chan…too much…”

Senkuu slowed his pace but added another finger, causing Gen to gasp for air. Looking down, Senkuu noticed how incredibly hard Gen had become in just this short amount of time. “Only 1 minute and 4 seconds have passed, and you’re already like this?” 

“Don’t…touch it.” Gen caught his breath. “I know I will get cola today.”

Senkuu was impressed by Gen’s determination. “Get on your hands and knees.”

Gen obediently listened and got into the position. He felt slightly embarrassed since his ass was in the air, and everything was visible for Senkuu to see.

Senkuu began massaging Gen’s ass cheeks with both of his hands before bringing his tongue to Gen’s hole.

Gen was shocked. “Senkuu-chan!” He exclaimed. “It’s dirty…nghh…ahhh…no…”

Senkuu ignored all of Gen’s protests. He felt Gen’s body quiver under his hands and could not resist the urge to make Gen feel good.

Senkuu licked around Gen’s entrance, occasionally poking his tongue inside. He proceeded to dip his finger in some more lube and began fingering Gen once again while kissing and biting his ass cheeks.

Gen was completely erect, but he focused hard to delay his orgasm.  _ I know I can get my cola today… _

After another minute, Senkuu grabbed the anal beads and started covering them in lube.

Gen tried to look behind him, but it was hard to see from the position he was in. He anxiously awaited Senkuu’s touch. His body began to shiver as Senkuu brought the smallest bead to his hole.

Senkuu pushed the bead inside and then immediately pushed the next one in as well. Senkuu pulled on the beads a little bit before inserting the next one, causing Gen to mumble and grip onto the pallet, anticipating the next bead.

“Do you like it Gen?” Senkuu probed. “Your ass is just sucking these beads up.”

Gen blushed while pushing his face into the pallet.

Senku abruptly pushed three more beads inside.

“Ahhh…nghhh…” Gen moans were muffled but sounded a bit louder than usual.

“Are you okay Gen?”

“…yeah…keep going…it…feels good.”

Senkuu proceeded to push the rest of the beads into Gen’s ass that resulted in Gen producing a sound Senkuu had never heard before.

Gen could feel all the beads inside him. It felt weird yet arousing—he couldn’t quite describe the exact feeling. All he knew was that he didn’t want Senkuu to stop.

Senkuu came close to Gen’s face and whispered into his ear, “You like that Gen? Having all these beads inside your ass? It’s been five minutes” Senkuu kissed Gen’s ear, causing them to redden. “Want me to pull them out?"

“Senkuu-chan…AHHH.” Gen couldn’t control his moans as Senkuu pulled out two beads and pushed them back in. 

Gen moaned so loud, even Chrome could hear through his sound-proof headphones. “What the fuck are they even doing up there?” Chrome momentarily wondered, but came to the realization that he probably doesn’t want to know.

Senkuu continued pulling some beads out and pushing them back in. “Senkuu-chan…faster.”

Senkuu was so surprised by Gen’s words that he blushed. “Okay, Gen.” He inserted all the beads and quickly pulled them out, Gen moaning as each bead was removed.

Gen felt his cock becoming unbelievably harder than it was before. He wanted to touch himself so badly but thought about how he wouldn’t get cola if he did. “Senku-chan…how much longer…”

“Two more minutes.”

Gen didn’t know if he could resist the impulse to touch himself.  _ Just a little bit wouldn’t hurt.  _ He reached his arm back in order to grab his cock but caught Senkuu’s eye in the process. 

“Go ahead and touch it,” Senkuu laughed. “If you don’t want your cola…”

Gen could tell by the tone of Senkuu’s voice that he was obviously teasing him. It was very tempting to just come right now, but Gen felt as though he could actually get cola today. He decided to retreat his arm.

Senkuu pulled out all the beads. “Gen, can you actually hold your ass cheeks apart?”

Gen turned his head to the side, trying to look back as much as he could. “Okay, Senku-chan.” He reached back and held both of his cheeks, spreading them apart—and feeling extremely embarrassed.  _ Senkuu-chan can really see everything now. _

Senkuu looked down, and seeing how vulnerable Gen was made him feel aroused—he had to resist pulling his cock out and getting himself off. He quickly shook off thoughts of pleasuring himself and had to think of a way to make Gen come in one and a half minutes.

He inserted the beads one-by-one back into Gen’s hole.

“Nghh…ahhh…ahhh!” Moans continuously exited Gen’s mouth. His grip on his own cheeks became tighter as Senkuu started pulling out the beads and pushing them back in.

“Senkuu-chan…touch me please…I can’t take it anymore.”

“Gen, you only have a minute left. Are you sure?” Senkuu was completely ready to finish Gen off, but he had to ask.

“You’re right…nghhh…keep going…ahhh…don’t stop Senkuu-chan!”

Senkuu proceeded to push in all the beads and quickly pull them out again, hearing all the sexy sounds Gen made.

“Senkuu…chan…I don’t think…I don’t…ahhhh!”

Gen couldn’t even finish his sentence before coming all over the pallet and rolling over on his side. He looked into Senkuu’s eyes, taking some deep breaths before speaking again. “Did I make it…Senkuu-chan…I must have…”

Senkuu shook his head. “Sorry Gen, you had fifteen seconds left…”

“Dammit!”

Senkuu laid down next to Gen and stroked his hair out of his face. “So close.” He leaned in and kissed Gen tenderly.

Gen ended up sitting on top of Senkuu, feeling his erection below him. “Want some help Senkuu-chan?” Gen breathed across Senkuu’s lips as he reached down, grabbing onto Senkuu’s cock.

Senkuu smirked. “Round two?”

**Notes for the Chapter:**

> i hope gen gets his cola soon...it's all up to senkuu 
> 
> almost done with chapter 4, so it should be posted soon(ish)!


	4. Chapter 4

**Summary for the Chapter:**

> Senkuu invents a dildo.

**Notes for the Chapter:**

> Gen's getting real desperate for this cola and Senkuu is all for it oop lol

“I really want some cola  ♪” Chrome heard from below the observatory. He occasionally would hear Gen sing whenever he was alone in the observatory.  _ Gen has a nice voice,  _ he thought to himself.

“Senkuu-chan!” Gen wailed.

“Time to put on my headphones,” Chrome said before putting them on and attempting to go to sleep.

“Hi Gen,” Senkuu responded, greeting Gen with a hug. 

Gen felt something hard poking him as he and Senkuu hugged. He reached down to feel whatever it was. “What’s this Senkuu-chan?” Gen smirked as he gripped onto it.

“Pull it out,” Senkuu laughed.

Gen reached into Senkuu’s pocket and pulled out a hard, silicon object— “A dildo!”

“Think you can get your cola today?”

Gen swallowed. He knew that he came extremely close to getting his cola the previous night, so he felt oddly determined, but at the same time nervous that this would be a repeat of last time.

Regardless of the possible outcomes, Gen was ready to be touched by Senkuu once again. He leaned into Senkuu's face, pausing before their lips could touch. “Make me come.” He kissed him. “Sen. Kuu. Chan.”

Senkuu grabbed Gen by his shoulders, tossing him onto the pallet. He gripped onto his wrists, pinned him down and greeted his lips with a kiss.

Senkuu was positioned in between Gen’s legs that were slightly spread apart. He rubbed his crotch against Gen’s, causing their cocks to become more erect.

“Does this count for my eight minutes?” Gen joked.

Senkuu smiled, not answering the question, then proceeded to remove Gen’s clothing. “I’ll let you know,” he teased.

He continued to kiss Gen, grazing his tongue against his lips—to which Gen allowed access to enter. Senkuu moved his tongue around the soft insides of Gen’s mouth, trying to savor the taste of Gen.

Senkuu dipped his fingers into his jar of lube. Gen felt Senkuu’s finger toying with his hole—slowly poking the tip inside until he felt it relax enough to insert his entire finger.

“Mmmm…”

Senkuu continued to finger Gen, slowly increasing his speed. Gen’s hole tightened around his finger and every time Senkuu entered, Gen expelled a moan. Senkuu added another finger and pumped a couple of times before taking both of his fingers out.

Gen let out some heavy breaths and gave Senkuu a somewhat desperate look. Senkuu picked up the dildo and began to rub lube all over it.

He rubbed the tip of the dildo on Gen’s entrance, slightly pushing it inside. With every thrust, Senkuu continuously pushed deeper and deeper. He finally heard a specific moan indicating that Senkuu hit Gen’s prostate. He rhythmically kept pushing in the dildo at the same spot.

“How long,” Gen moaned. “How long…ngh…has it been?”

“2 minutes and 5 seconds,” Senkuu answered as he pushed the dildo as deep as he could.

“Ahhhh!” Gen moaned. He grabbed Senkuu’s wrist. “Please…Senkuu-chan…you’re going to make me cum.”

Senkuu abruptly pulled out the dildo. “Turn around.”

Gen obediently followed Senkuu’s demands and raised his ass into the air. Senkuu continued to pump the dildo in and out of Gen’s ass. The visual was absolutely arousing—Senkuu couldn’t help but use his other hand to rub his own cock.

Gen’s head was turned to the side as he let out elongated, breathy moans. However, Gen noticed that his moans weren’t the only ones filling the room.

“Mmmm…nghh…” Gen heard and thought,  _ Is Senkuu moaning? _ He attempted to turn his head back and take a look, but unfortunately couldn’t see anything. His questioning thoughts were shortened due to the fast and deep thrusts Senkuu gave.

Senkuu couldn’t deny how pretty Gen was. He flipped him around. “I want to see you do it to yourself.”

Gen’s eye immediately went to Senkuu’s cock that was gripped by his left hand, slowly stroking the entire length. Gen’s already reddened face became implausibly redder.

Senkuu jerked himself off as he watched Gen push the dildo inside himself. “Faster, Gen.”

Gen pushed the dildo harder and faster. Seeing Senkuu touch himself turned Gen on even more, leaving him unsure of how much longer he could last. “Senkuu-chan…I-I don’t…”

Senkuu prevented Gen from finishing his sentence by laying over him and planting a kiss upon his lips. He also rubbed his cock together with Gen’s, using the precum to reduce the friction.

“Hahhh…Senkuu-chan, you’re…you’re going to make me come….” Gen paused to let out a few moans. “How much longer?”

Senkuu lifted his head to make direct eye contact with Gen. “3 and a half more minutes.”

Gen felt the desire to come but withheld that feeling as much as he could. “Senkuu-chan…it’s not fair—I’m supposed to just come with the dildo.”

Senkuu got up, separating their cocks. “Sorry, I got carried away. Want me to do it?”

Gen didn’t respond for a moment, leading to Senkuu grabbing the dildo once again, steadfastly pumping it into Gen’s ass.

“Senkuu-chan…ahhhh…I want you inside me.”

Senkuu blushed. “You think you’d be able to handle it, Gen?” Senkuu smiled and pumped the dildo at a ridiculously fast pace.

Gen let out curt moans that were even louder than before. “I’m coming!”

Senkuu couldn’t stop fucking Gen with the dildo, he wanted to see all of his erotic faces. It had only been five minutes, but Senkuu had to see the face Gen made when he came—it was beautifully pornographic.

Gen grabbed his own cock and quickly jerked his hand to accelerate his orgasm. Cum dripped down his hand as he held onto his cock and rode out his orgasm.

Senkuu slowly pulled out the dildo. Gen’s body still trembled from the overwhelming amount of stimulation he had just experienced.

“Gen, you only lasted…hahh!”

Gen’s mouth wrapped around Senkuu’s still erect cock. Senkuu combed his fingers through Gen’s hair as he continuously bobbed his head up and down.

Gen briefly lifted his head. “I know I’m not getting my cola today.” He moved his tongue around the head of Senkuu’s cock, causing Senkuu to tense up. “But it’s okay, Senkuu-chan. I’ll definitely get it tomorrow.” Gen winked before taking Senkuu into his mouth again.

The softness of Gen’s mouth titillated Senkuu’s cock to the max. It was a completely pleasurable sensation that made Senkuu feel the urge to jerk his hips into the air.

Before doing so, Gen pushed Senkuu’s cock all the way to the back of his throat that wrapped around his cock so tightly. “Gen…shit, that feels so good…nghh.”

Gen lifted his head, holding Senkuu’s cock with his hand and slowly jerked him off. “Are you about to come, Senkuu-chan?” Gen grinned while jerking him even faster.

Senkuu’s cock throbbed within Gen’s grasp. “Ahhh…Asagiri Gen…”

Gen gazed into Senkuu’s eyes before taking him into his mouth once again. Senkuu came into Gen’s mouth. He swallowed, then licked up the cum that remained.

“Can I get cola for this?”

Senkuu laughed and kissed Gen’s lips where the lingering taste of himself remained. He moved his face towards Gen’s ear and stuck his tongue inside causing Gen to flinch.

“Maybe you’ll last eight minutes tomorrow…nghh”

Gen gripped onto Senkuu’s extremely sensitive cock and rubbed his thumb on the head. “Fine, Senkuu-chan! I’ll be sure to last tomorrow.”

Gen got up to clean himself off, then returned back to the pallet where Senkuu had laid down. He laid next to Senkuu, snuggling his head into Senkuu’s chest.

“Good night, Senkuu-chan.”

Senkuu pulled Gen closer. “Sleep well, Gen.”

**Notes for the Chapter:**

> Gen's official time was 5 minutes an 8 seconds
> 
> next chapter will be the last! 
> 
> y'all aren't even ready tbh *eyes looking emoji*


	5. Chapter 5

**Summary for the Chapter:**

> Senkuu invents bondage.

**Notes for the Chapter:**

> Well here it is! I hope you guys enjoy the last chapter as much as I enjoyed writing it (*´▽`*)

Gen swung open the door to the observatory with sheer determination. “Senkuu-chan! I’M GETTING MY COLA TODAY,” he declared.

Senkuu, who was sitting by the telescope, turned around to greet him with the most cynical smile Gen had ever seen. “Well, hello Gen.”

Gen tensed up a bit. Although he had seen plenty of the  _ inventions _ Senkuu made, Gen couldn’t even imagine what he had in store for him this time, especially with that pixelated look on his face. “Ahh…Senkuu-chan, what did you make today?”

“Nothing  _ too  _ new…” Senkuu laughed, then immediately walked over to the side of the room, grabbing a bag and took it to the pallet where he sat down.

Gen’s eyes widened.  _ Nothing too new? What could that mean? _

“Come here, Gen.” Senkuu smiled as he patted a spot on the pallet.

Gen apprehensively made his way to Senkuu and knelt down next to him. “What’s in the bag?”

Senkuu proceeded to pour familiar objects out of the bag—the lube, flesh light, anal beads, dildo, and… “Rope?” Gen questioned as he picked up the rope, examining it. It was about 30 feet long, and Gen was confused as to what the purpose of this rope was. “Why? Are you trying to kill me?!”

Senkuu couldn’t control the endless stream of maniacal laughter that exited his mouth. He grabbed the rope and wrapped it around Gen’s wrist. “We’re going to try bondage today…plus everything we’ve used before.”

“EVERYTHING?!” Gen was dumbfounded.  _ How the hell am I supposed to last 8 minutes?  _ “Senkuu-chan,” he whined, forcing tears to form in his eyes. “But I want my cola…I don’t think I can last 8 minutes with all of this…”

Senkuu’s smile became slightly more twisted. “That’s the point Gen…I want to see how much you actually want your cola.”

Gen agreed to Senkuu’s conditions as usual and stripped off his clothes.

Senkuu took the rope and began wrapping it around Gen in intricate ways, pulling it tightly in specific regions. “I’m doing a tie called  _ Hishi Karada, _ it’s also called a rope dress.”

Although Senkuu was simply tying Gen up, it was extremely arousing. The way the rope tightly gripped onto his body made his cock twitch and nipples hardened. It didn’t take too long for Senkuu to notice. “Maybe you’re right Gen. You’re already this turned on—”

Gen hesitated because he somewhat agreed with Senkuu, but he rebutted, “No! I will get my cola Senkuu-chan!”

Senkuu saw the glimmer of determination in Gen’s eyes. “You must really love cola,” Senkuu bantered. “Let’s choose a safe word, just in case you want to stop.”

“Hatsune Miku.” Gen immediately chose with no hesitation.

“One of those singing voice synthesizers?”

“Uhh…yes.”

Senkuu finished tying Gen up. “What should I use first?” He indecisively looked at all the toys he made, picking each one up and observing it.

He decided to first get some lube to rub onto Gen’s semi-erect cock, giving it a few pumps before grabbing the flesh light and putting some lube inside it. Placing the flesh light at Gen’s tip, he pushed down, making Gen’s cock enter the flesh light completely.

“Senkuu-chan…it’s so tight…”

“Because I have it on the maximum tightness…” Senkuu covered his finger in lube and rubbed it against Gen’s hole before shoving it inside, causing Gen to let out a soft moan. 

Simultaneously, Senkuu pumped the flesh light and fingered Gen’s ass, increasingly adding more fingers until Gen’s hole was stretched out enough. Senkuu took the dildo and covered it in lube, then immediately pushed it inside Gen’s ass. 

“Hahhhh!” Gen whined as Senkuu penetrated him, pushing the dildo as deep as he could with every stroke. Gen felt as though he no longer had any control over his body. “Senkuu-chan...how long?”

“2 minutes and 36 seconds.” Senkuu started pumping the flesh light extremely fast.

“Ahhhh!” Gen cried out. Although both his cock and ass were being stimulated, Gen persisted on lasting the whole 8 minutes...no matter what.

Soon, Senkuu pulled out the dildo, removed the flesh light, and picked up the anal beads. Gen took a moment to compose himself while Senkuu prepared the beads.

“Turn around,” Senkuu seductively commanded and Gen obeyed, getting on all fours. 

Senkuu pushed all the beads into Gen’s ass, which made him moan loudly. He thrusted the beads into Gen, increasing the pace with each thrust. Gen’s body quivered and he could barely hold his ass in the air since his body felt weak. “Senkuu-chan...ahhhh...”

“Don’t tell me you’re thinking about coming already?” Senkuu teased.

“Of...nghhhh...course not...do it faster.”

“If that’s what you want Gen.” Senkuu increased his pace. Gen tightly gripped onto the pallet, with heavy breaths and moans escaping his mouth as he felt each individual bead enter and exit his ass. “Your ass must be getting used to this Gen...it’s already been over 3 minutes.”

Senkuu couldn’t see, but a smile fell upon Gen’s face. He turned his head enough to meet Senkuu’s eyes and temptingly licked his lips, making Senkuu momentarily flustered—made obvious by the blush that appeared on his cheeks.

The beads were completely pulled out and immediately replaced by the dildo. Gen squealed because of the rapid exchange. “Senkuu-chan!”

Senkuu laughed as he rapidly thrusted the dildo into Gen’s ass, watching Gen’s dripping wet cock bounce around with each assertive entry. Senkuu noticed that his own cock had become erect, but he resisted touching himself in order to focus on making Gen come.

“Senkuu-chan...ahhh...”

“Are you about to come?” Senkuu teased.

“N-Nghh...no. I want you to fuck me Senkuu-chan. Ahhhh...with your big cock! I want you inside me...”

Senkuu’s face became even redder. His hand reached towards his cock, but he stopped himself.

“I know you want to touch it, Senkuu-chan...touch yourself...”

Instead of touching himself, Senkuu pushed the dildo harder and deeper into Gen. However, the sound of Gen panting turned him on so much to the point that Senkuu let out a quiet moan.

The moan was loud enough for Gen to hear, but he pretended as though he didn’t—he had  _ other  _ plans. 

“Senkuu-chan...fuck me please,” Gen drawled on. “Wouldn’t you rather see your cock inside me instead of this dildo...nghh.”

Senkuu indeed would love to put his cock inside Gen, feeling him tighten around him...but that wasn’t his current objective. “Stop trying to tempt me you mentalist,” Senkuu retorted, pushing the dildo in quickly.

“Ahhhh,” Gen cried out. “I bet you’ve used all these toys on yourself, haven’t you?”

Senkuu didn’t respond. He had most definitely tested out all these toys before...but that wasn’t something he wanted to admit to Gen. “Your mind games won’t work on me...”

“Hah...” Gen panted as Senkuu continued to fuck him with the dildo. He was sure Senkuu had used the toys before, based on his answer. “Haaaa...H-HATSUNE MIKU!”

“Huh? Hatsune Mi—oh yeah!” Senkuu pulled out the dildo, surprised by Gen’s use of the safe word that he completely forgot about. “You want to stop?”

Gen turned around and started pulling on Senkuu’s dress. “No...I want you to fuck—”

Before being able to even finish his sentence, Senkuu grabbed onto Gen’s shoulders and pinned him down. “Fine!” 

He lifted his dress enough to reveal his fully erect cock. With no hesitation, he pushed his cock into Gen, stroking quick and hard. Their faces were only inches apart from each other, lips barely touching. 

Senkuu was rough. The way he thrusted made Gen worried that he wouldn’t last long enough to get his cola. “Senku-chan...hahhh...long?” These were the only words he could get out.

“6 minutes...nghh...38 seconds,” Senkuu responded before grabbing onto the ropes tied around Gen’s hips, pulling him in sync with his thrusts causing his cock to go deeper than before.

Gen cried out louder than Senkuu had ever heard, it was definitely loud enough to leak outside of the observatory...

* * *

“OH. MY. GOD! I can’t take this!” Chrome shouted as he decided to leave his room for the night. Gen’s moans were so loud that even his sound proof headphones weren’t enough.

He walked over to the bridge where he saw Ginro and Kinro whose faces looked a bit traumatized. 

“What’s wrong with you guys?” Chrome questioned the two of them.

“We heard some  _ shrieking  _ coming from the observatory...” Kinro admitted.

“Gen and Senkuu are up there aren’t they?!” Ginro questioned with a sort of excited tone and a perverted look on his face.

“You guys don’t even know...” Chrome sighed as he went on to explain his daily routine on how to deal with Gen and Senkuu’s  _ alone time. _

* * *

_ 2 more minutes. 2 more minutes.  _ Gen repeated this in his mind, trying to focus on not coming as Senkuu pounded into him. He often wanted to just forget about the whole time limit thing and come right then, because having Senkuu inside him felt so fucking good...

“Gen...ahhh...I’m about to come.”

Gen was shocked.  _ Senkuu-chan is about to come...BEFORE ME!? _

Gen decided to take advantage of this opportunity. He pushed Senkuu back and settled himself on top of him. Shoving Senkuu’s cock back into his ass, he rode him—alternating between slamming his ass down on his cock and grinding against it.

Senkuu held onto the ropes along Gen’s waist, pulling him down as he slightly lifted his hips up. “Gen...I-I love you...” This was the last thing Senkuu said before coming into Gen’s ass.

Moments later, Gen came as well. He was in complete shock of Senkuu’s words. It was the second time he had ever heard Senkuu say that he loved him. 

Gen laid himself down next to Senkuu, panting heavily. “Senkuu-chan, can you say it again?”

Senkuu caught his breath and his cheeks blossomed. “Say what?”

Gen jokingly shoved Senkuu before getting back on top of him, placing a kiss on his lips. “I love you too.”

“You’re so gross.”

“I know,” Gen laughed. “So...how long did I last?” Gen had the most desperate look on his face. He really wanted some damn cola.

Senkuu wrapped his arms around Gen. “Congrats, you lasted 8 minutes and 5 seconds.”

Gen’s face lit up. “Finally! I can finally get my cola!” He shouted out in a sing-song voice. Another thought loomed in his mind however. “By the way Senkuu-chan...did you actually use all the toys on yourself?”

Senkuu’s face somehow became redder than it already was. “Yes...” He admitted. “This was actually all part of an experiment I have been conducting...” 

Gen wasn’t surprised at all. Everything made sense, all the time limits and different toys used as controls.

Senkuu continued to explain, “I was curious about the human body and orgasm. The only person I’d even want to use as a test subject, other than myself of course, is you Gen.”

Gen blushed. “Now you’re being gross Senkuu-chan,” Gen teased as he laid back down next to Senkuu.

Senkuu laughed as he walked over to a mini fridge that sat in the corner of the observatory. Inside contained all the ingredients necessary to make cola. Senkuu prepared the cola and brought it over to Gen. “You’ve earned it.”

Gen twisted open the top and heard the familiar sizzle of the carbonation that he loved so much. He chugged the cola, feeling all the fizzles slide down his throat and foam oozing out the sides of his mouth. It was the best cola he ever had.

**Notes for the Chapter:**

> That's all folks!
> 
> and in case you wanted to know, here are Senkuu's resulting times when he used the toys on himself
> 
> -just lube & hand job: 9 minutes  
> -flesh light: 5 minutes  
> -anal beads: 7 mins  
> -dildo: 7.5 mins  
> -everything (minus bondage): 6 mins


End file.
